Synthesis and anti-proliferative activity of allogibberic acid derivatives containing 1,2,3-triazole pharmacophore.

Sixty novel allogibberic acid derivatives containing 1,2,3-triazole pharmacophore were designed and synthesized. The key chemical processes include aromatization of the A ring in gibberellins, formation of allogibberic azides and its copper mediated Huisgen 1,3-dipolar cycloaddition with alkynes. A number of hybrids containing α,ß-unsaturated ketone moiety exhibited excellent in vitro cytotoxic activities. Some of the hybrids were more selective to MCF-7 and SW480 cell lines with IC50 values at least 8-fold more cytotoxic than cisplatin (DDP). The most potent compounds C43 and C45 are more cytotoxic than cisplatin (DDP) against all tested five tumor cell lines, with IC50 values of 0.25-1.72 µM. Mechanism of action studies indicated that allogibberic-triazole derivative C45 could induce the S phase cell cycle arrest and apoptosis in SMMC-7721 cell lines.